Sion Sono--as with counterpart Takashi Miike--has a wonderful knack for making satirical, ridiculous horror that remains oddly frightening and tense, amidst the jokes and parodies. Despite Exte's premise (hair extensions, deadly ones,) it has more in common with Higuchinsky's surreal, silly opus Uzumaki than it does your standard cursed-object-of-the-moment scare fare. If you've started to roll your eyes at the immeasurable amount of scenes featuring long, black hair in a sinister manner, this movie is for you. Sion Sono seems to think the device has gotten out of hand, too, and this is his antidote: give them so much hair, and nothing but hair, that they'll realize how stupid it is!
But to make sure it's not an obvious criticism of flimsy horror, he also includes some stuff that could be considered pretty straight-faced; there's a subplot/backstory involving organ harvesting and human trafficking, as well as a squirm-inducing child abuse tangent. But I don't think it would be spoiling it to say that the baddies get what they deserve, in hilarious and satisfyingly outrageous ways.
It also doesn't hurt that the cast is extremely likable. Our heroine--who is, of course, a hair stylist--is played by the recognizable face of Chiaki Kuriyama. The ladies playing her perky roommate, evil half-sister, and adorable niece are also stellar. However, the show belongs to the great Ren Osugi (Nightmare Detective, Loft, and hundreds of other appearances) who holds nothing back and will most certainly make you bust a gut laughing...if you like this sort of thing, that is. His strange get-up of American flag-adorned clothing and white, Mickey Mouse style gloves alone is worth seeking this movie out. Thankfully, the rest of it holds up just as well.